Summary and Implications
Designating correct contemporary groupings is important in reporting performance traits in beef cattle performance programs. An analysis of 166 bulls over a three-year period showed that grouping all cattle into one contemporary group each year lead to major errors in evaluating sires for their average feed intake, feed conversion and residual feed intake (RFI). Under this grouping strategy, sire progeny averages were estimated incorrectly; 58% of sire averages for dry matter intake were off by .5 lbs daily or more, 25% were off by .5 lbs or more in feed conversion and 67% were off by .5 lb or more for RFI. Also 25%, 29% and 33% were estimated with the wrong sign for dry matter intake, feed:gain ratio and RFI, respectively, which means sire progeny averages either received a positive sign for the trait rather than negative, or vice versa.
Iowa State University
Strohbehn, Daryl R. and Dahlke, Garland
"Impact of Contemporary Group Assignment on Sire Means in
Feed Efficiency Testing,"
Animal Industry Report:
AS 655, ASL R2398.
Available at: http://lib.dr.iastate.edu/ans_air/vol655/iss1/21